Linux directory structure explained

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Remembering what all the default directories in Linux are for, can be hard at first. Here is a little “cheat sheet” that shows the Linux directory structure.
linux directory structure

/ – Root

  • Every single file and directory starts from the root directory.
  • Only root user has write privilege under this directory.
  • Please note that /root is root user’s home directory, which is not same as /.

/bin – User Binaries

  • Contains binary executables.
  • Common linux commands you need to use in single-user modes are located under this directory.
  • Commands used by all the users of the system are located here.
  • For example: ps, ls, ping, grep, cp.

/sbin – System Binaries

  • Just like /bin, /sbin also contains binary executables.
  • But, the linux commands located under this directory are used typically by system aministrator, for system maintenance purpose.
  • For example: iptables, reboot, fdisk, ifconfig, swapon

/etc – Configuration Files

  • Contains configuration files required by all programs.
  • This also contains startup and shutdown shell scripts used to start/stop individual programs.
  • For example: /etc/resolv.conf, /etc/logrotate.conf

/dev – Device Files

  • Contains device files.
  • These include terminal devices, usb, or any device attached to the system.
  • For example: /dev/tty1, /dev/usbmon0

/proc – Process Information

  • Contains information about system process.
  • This is a pseudo filesystem contains information about running process. For example: /proc/{pid} directory contains information about the process with that particular pid.
  • This is a virtual filesystem with text information about system resources. For example: /proc/uptime

/var – Variable Files

  • var stands for variable files.
  • Content of the files that are expected to grow can be found under this directory.
  • This includes — system log files (/var/log); packages and database files (/var/lib); emails (/var/mail); print queues (/var/spool); lock files (/var/lock); temp files needed across reboots (/var/tmp);

/tmp – Temporary Files

  • Directory that contains temporary files created by system and users.
  • Files under this directory are deleted when system is rebooted.

/usr – User Programs (Unix System Resources)

  • Also known as short for “Unix System Resources”
  • Contains binaries, libraries, documentation, and source-code for second level programs.
  • /usr/bin contains binary files for user programs. If you can’t find a user binary under /bin, look under /usr/bin. For example: at, awk, cc, less, scp
  • /usr/sbin contains binary files for system administrators. If you can’t find a system binary under /sbin, look under /usr/sbin. For example: atd, cron, sshd, useradd, userdel
  • /usr/lib contains libraries for /usr/bin and /usr/sbin
  • /usr/local contains users programs that you install from source. For example, when you install apache from source, it goes under /usr/local/apache2

/home – Home Directories

  • Home directories for all users to store their personal files.
  • For example: /home/john, /home/brian

/boot – Boot Loader Files

  • Contains boot loader related files.
  • Kernel initrd, vmlinux, grub files are located under /boot
  • For example: initrd.img-2.6.32-24-generic, vmlinuz-2.6.32-24-generic

/lib – System Libraries

  • Contains library files that supports the binaries located under /bin and /sbin
  • Library filenames are either ld* or lib*.so.*
  • For example: ld-2.11.1.so, libncurses.so.5.7

/opt – Optional add-on Applications

  • opt stands for optional.
  • Contains add-on applications from individual vendors.
  • add-on applications should be installed under either /opt/ or /opt/ sub-directory.

/mnt – Mount Directory

  • Temporary mount directory where sysadmins can mount filesystems.

/media – Removable Media Devices

  • Temporary mount directory for removable devices.
  • For examples, /media/cdrom for CD-ROM; /media/floppy for floppy drives; /media/cdrecorder for CD writer

/srv – Service Data

  • srv stands for service.
  • Contains server specific services related data.
  • For example, /srv/cvs contains CVS related data.

9 thoughts on “Linux directory structure explained

  1. Pingback: Booting and directory structure » Express Yourself

    1. Steffan Post author

      Modern Linux distributions include a /sys directory as a virtual filesystem (sysfs, comparable to /proc, which is a procfs), which stores and allows modification of the devices connected to the system, whereas many traditional UNIX and Unix-like operating systems use /sys as a symbolic link to the kernel source tree.
      (copy/pasted from wikipedia)

      Reply

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